The invention relates to an infusion set having a container for liquid medicines, which is connected to a drip chamber by a feed-line and a differential pressure valve and by a further feed-line connected to a front end being controlled by a roller clamp. A similar structure is disclosed in U.S. patent application Ser. No. 08/800,779, now issued as U.S. Pat. No. 5,935,100, which is hereby incorporated by reference. In the disclosed structure, the differential pressure valve has two inlets, each with an associated differential force chamber, wherein the two differential force chambers are sealingly separated from each other by a diaphragm disk and, wherein further the two differential force chambers together are connected to an exit line for the liquid medicine.
In the infusion set according to U.S. patent application Ser. No. 08/800,779, the differential pressure valve is performed such that it is used to empty sequentially a number of containers filled with liquid medicines in a controlled way.
In known infusion sets, an additional check valve is necessary to prevent a contamination of the set in the case of an occlusion or the like. Further, in many cases, it is necessary while the infusion is going on to administer additional amounts in a surge-like manner or to additionally inject, for example, contrast substances.